HP 250C - Manual (Page 57)

5Ć15 Functional Overview C4699Ć90000
Power Supply
An autoĆranging power supply is locatedin the electronics module.
(Specifications ' chapter 1, Power Requirements.")
The primary side of the power supply contains rectified line
voltage that can be lethal when touched even if the ON/OFF
switch is OFF.
In any case, youshould not need to open the electronics
module. It is one exchangeable part.
W A R N I N G
Water Condensation
In humid environments, water may condense on the sideĆplates. A wick attached to the
underside of the right sideĆplate routes water drops away from the mainĆPCA electronics.
Memory Usage
It is difficult to calculate the amount of plotter memory needed to plot a drawing of any given
file size. Memory is used, not just to hold the input data, but also for system overhead,
processing workĆspace, andstorage of the internal representation of the plot. Some types of
graphics require relatively large amounts of memory. Examples are wide lines, raster fill
patterns, polygons, anduserĆdefinedlines.
Plot Orientation
The output orientation of the drawing also has an impact on memory usage. Compare a plot
of horizontal lines with one of vertical lines. Lines plottedparallel to the carriage axis take
up considerably less memory than those plotted perpendicular to it. The plotter builds
graphic display objects on a swathĆbyĆswath basis. A horizontal line can be contained in one
swath. A vertical line spans many swaths andtherefore requires more entries in the plotter's
internal display list.
Raster Image Processor
The raster transfer language (RTL) provides a solution to insufficient memory on the plotter.
When all the data is sent to the plotter in the order leftĆtoĆright and topĆtoĆbottom, the
plotter is able to plot the data as it receives it. For this to happen, software (a rasterĆimage
processor) in the computer must first rasterize all the data. The software issues a command
(referredto in RTL as no negative motion) telling the plotter that it will not receive data
for any media location on which it has already plotted.
The use of no negative motion is called flow mode. Data flows through the plotter without
being storedin a display list, so the size of the file that you can sendis almost unlimited.